Drafting tables with storage cabinets and drawers disposed beneath the table tops are well known in the art as illustrated, for example, in U.S Pat. No. 3,273,517. Such cabinetry is, however, an integral part of each table and ordinarily cannot be modified to suit the particular needs or desires of different customers. A need exists, therefore, for a drafting table having a frame which serves as a skeleton to which different combinations of file units, drawer units, shelf units, and the like, may be secured to meet the specific preferences and requirements of users.
Despite its skeleton frame construction, such a frame should provide the advantages of counterbalancing and self-leveling found in premium quality drafting tables. While counterbalancing and/or self-leveling mechanisms are known (see, for example, U.S. Pat. Nos. 3,370,556, 3,213,809, and 2,982,050), applicants are unaware of any prior construction in which such mechanisms are completely contained within the members of a generally U-shaped frame so as to leave ample room within the opening defined by the frame members for supporting an arrangement of selected modular storage units. Other patents of general interest are U.S. Pat. Nos. 2,560,928, 3,381,634, 3,364,881, and 3,283,731.
In brief summary, this invention is concerned with an open-frame two-post drafting table having a base, the base including a horizontal base beam and a pair of upstanding telescoping columns at opposite ends of that beam. Each column includes generally tubular upper and lower column sections, the lower sections being secured to the base beam and the upper sections being slidably extendable and retractable relative to the lower sections. Means are provided within the base beam and the telescoping columns for counterbalancing the upper sections and the table top carried thereby and for synchronizing the movement of the upper telescoping sections to insure self-leveling of the table top regardless of its position of vertical adjustment. The counterbalancing and synchronizing means includes a cable which, in the embodiment disclosed, extends in an endless loop through the base beam and into each of the columns. Friction-reducing guide means in the form of pulleys are disposed within each of the columns, and within the base at its opposite ends, for supporting and guiding movement of the loop of cable. The loop has a pair of vertically-extending stretches disposed within each of the columns, the stretches being movable in opposite vertical directions as the endless loop of cable travels one way or the other. The upper sections of the respective columns are secured to those stretches of cable which travel in the same vertical direction within the columns, and spring means disposed within the hollow base urges the loop of cable in one direction to counterbalance the weight of the upper column sections and the top supported thereby. Adjustment of the counterbalancing force may be achieved simply by altering the points at which the upper sections of the columns are secured to the control cable. Since the entire counterbalancing and self-leveling mechanisms are housed within the hollow frame members, and since such members are relatively narrow, leaving a large space between the upstanding columns, various modular units or arrangements of such units may be supported within the space to meet the needs and preferences of users. Furthermore, such arrangements may be modified from time to time as needs change without in any way affecting the counterbalancing and self-leveling mechanism housed within the frame.
Further advantages and objects of the invention will become apparent from the specification and drawings.